The reason I ask about FIV is because some years ago I adopted a female cat Mair from a rehoming centre and successfully integrated her into my home with the lovely 16 year old kitty, Emily, that I had at the time and after a month Mair just went from a happy healthy looking cat, to a cat that couldn't regulate her own body temperature, has discharge from her nose and eyes and she just stopped eating and lost a huge amount of weight in days. She just shivered the weight off. I took her to the vets, the first day she showed any signs of illness, they tested her and after a week they called me and told me she had FIV and loads of complications because of that and the only kind thing to do was put her to sleep. Then they told me I had to get Emily tested as she could have FIV too. It broke my heart to have to put Mair to sleep and then I spent a terrified week waiting for Emily's blood test results to come back. Thankfully Emily didn't have FIV and she lived on until she was 21 years old.
This was all some years ago when FIV wasn't so well known about and wasn't so regularly tested for, so I don't blame the rehoming centre for not knowing and telling me, but I still feel to this day that if I had known and I had more knowledge of Mairs condition when I got her, she may have survived longer and or she might have stood more of a chance of a long happy life. To this day I feel like I let her down, hence I just feel the need to know as much as I can, so I can research if I am able to give the kitties I take in the best lives I can, however long or short those lives maybe.